7.4. Encapsulated ingredients and their applications

The following is a compilation of the most common ingredients available in an encapsulated form.

• Acidulants are added to foods for many different reasons. For example, they are used as flavour modifiers, preservation aids, and processing aids. In addition, they facilitate the development of a wide variety of textural effects because of their interaction with other constituents such as gums, pectins, proteins, and starches. Unencapsulated food acids can react with food ingredients to produce many undesirable effects. These include deceased shelf life of citrus-flavoured foods and starch-containing foods, lost of flavour, degradation of colour, and separation of ingredients. Encapsulated food acids resolve these and other problems because they preclude oxidation and provide controlled release, with their coating formulated to dissolve or melt at specific temperatures. Furthermore, encapsulated acids reduce hygroscopicity, reduced dusting, and provide a high degree of flowability without clumping. Examples of encapsulated acidulants that are commercially available are adipic acid, ascorbic acid, citric acid, fumaric acid, lactic acid, and malic acid.

  Several applications of encapsulated acidulants are given below.

  1. Dough Conditioners ® Ascorbic acid (vitamin C) as an oxidation agent in the strengthening and conditioning of bread and roll doughs produces many positive effects in the finished products. Among these are, e.g., stronger sidewalls, uniform crust colour, and improved slicing, in addition to a stronger structure, which supports the addition of other protein-rich ingredients (such as non-fat dry milk, soy flour, and wheat germ). However, because ascorbic acid degrades rapidly in presence of water and oxygen, most of the acid is degraded before it is needed. The encapsulated form protects the acid from the environment and releases it during the proofing and baking stages when it is needed most.

  2. Flavour Adjuncts ® in describing the importance of controlled release, Percel (1988) points out the difference in behaviour between encapsulated and uncoated citric acid added to tea for tartness. He said that uncoated citric acid could react with certain components of tea called tannins to discolour the tea bag - even before steeping. Substitution with an encapsulated citric acid precludes this reaction since the acid is released only upon dissolution of the coating and still delivers the desired amount of tartness.

  3. Meat processing aids ® Cured meat product, especially dry and semi-dry sausages (e.g., summer sausages, pepperoni, hard salami, and others) have historically been produced using lactic acid producing bacterial cultures to develop flavour and lower the pH. Such products often have inconsistent flavour, colour, and texture development from batch to batch. Uncoated lactic acid and citric cannot be used in the production of cured meats because they react almost instantaneously with the meat, rendering it unsuitable for further processing. However, an encapsulated acid, which is formulated for delayed release under smokehouse temperatures, can be used in alternative to the cultures. The encapsulated acid reproducibly produces the same pH and eliminates the need for fermentation. As a result, production time is reduced.

• Natural colours such as annato, b-carotene, and turmeric present solubility problems during their use and may create dust clouds. Encapsulated colours are easier to handle, and often improved solubility, stability to oxidation, and control over stratification from dry blends. Another advantage associated with their use is their extended shelf life, which can exceed two years compared to 6 months for the uncoated form.

• Flavouring agents and spices are encapsulated by a variety of processes and offer numerous advantages to the food processor. Citrus oil and other flavours, e.g., provide enhanced stability to oxidation, volatilisation, and light; controlled release; resistance to clumping and caking; and substantially longer shelf life.
  Mailard reaction products used in savory, meat, and seafood flavours are highly unstable in the liquid form and need to be convert to the dry or oil form. Encapsulation of these confers even greater stability.
  Encapsulated flavours are available as natural flavours, natural and artificial flavours, essential oils (menthol, peppermint, and spearmint), oleoresins, natural flavours with other natural flavours added, chips, and artificial flavours. Although encapsulated flavours may be used in many different applications, they are currently gaining considerable attention for they stability through high-temperature/short-time processes such as those utilised in preparing extruded foods and microwavable foods.
  Spices are encapsulated to extend shelf life, retain potency, and inhibit reactions with other ingredients. For example, cinnamaldehyde, a flavouring agent with natural antimicrobial properties present in cinnamon, can retard the growth of yeast in yeast- leavened baked goods. Fat-encapsulated cinnamon still contributes flavour to the baked products but does not interfere with the leavening process.

• Leavening agents are routinely used in baked goods to achieve volume and lightness of texture. Encapsulated sodium bicarbonate protects the base from premature reaction with acid or water, and delays the release of its contents until the optimum baking conditions are present. This ensures that maximum leaving is achieved and proves to be economically attractive. Encapsulates are produced with a variety of fat and oil coatings, which allow the food product developer more flexibility in optimising the formulation.

• Sodium chloride, encapsulated with a variety of coatings, including partially hydrogenated vegetable oil, is used in formulations to control colour degradation, rancidity, water absorption, and yeast growth. The encapsulated form also improves flowability and reduces clumping and caking. Typical product applications include communised meats, pretzel snacks, and yeast doughs.

• Sweeteners are, often subject to the effects of moisture and/or temperature. Encapsulation of sweeteners- namely sugars and other nutritive sweeteners - reduces their hygroscopicity, improves their flowability, and prolongs their sweetness perception.

• Vitamins and minerals are added to nutritional dry mixes to fortify a variety of foods, including breakfast cereals, dairy products, infantile formulas, and pet foods. Both fat- and water-soluble vitamins and minerals may be encapsulated with a variety of coatings to provide many advantages. Encapsulated reduces off-flavours contributed by certain vitamins and minerals, permits time release of the nutrients enhances stability of vitamins to extremes in temperature and moisture, and reduces each nutrient's reactivity with other ingredients. Encapsulation also improves flow properties and reduces dusting when the nutrients are added to dry mixes.